Method and an apparatus of leveling a metal strip

ABSTRACT

A method of working a thin metal strip comprising the step of: passing the metal strip along an elongated flat support having a thin roll thereon while pressing the thin roll against the strip by passing a pressurized fluid along the bearing surface between the support and the roll.

United States Patent [191 Miyamatsu et a1.

[ 4] METHOD AND AN APPARATUS OF LEVELING A METAL STRIP [75] Inventors: Yasunori Miyamatsu, Yokohama;

Arao Kamoi, Kudamatsu; Kinya Fukuda, Yokohama, all of Japan [73] Assignee: Toyo Kohan Co., Ltd., Tokyo, Japan [22] Filed: Dec. 14, 1972 [21] Appl. No.: 315,108

[52] U.S. C1. 72/163, 72/245 [51] Int. Cl B2ld 1/02 [58] Field of Search 72/160, 163, 245, 246,

[56] References Cited UNITED STATES PATENTS Biggert, Jr. 1. 72/245 1 1 May 28, 1974 Kusters 72/245 X Polakowski 72/163 Primary ExaminerMilton S. Mehr Attorney, Agent, or FirmGeorge B. Oujevolk [57] ABSTRACT A method of working a thin metal strip comprising the step of: passing the metal strip along an elongated flat support having a thin roll'thereon while pressing the thin roll against the strip by passing a pressurized fluid along the bearing surface between the support and the roll.

5 Claims, 7 Drawing Figures FATE-mum 1914 I 3812.701

SHEET 2 UP 6 FIG. 2

I PATENTEMvzs man I v sustrsp sf- METHOD AND AN APPARATUS OF LEVELING A METAL STRIP BACKGROUND OF THE INVENTION The present invention relates to a new and economic method and apparatus of leveling a metal strip which has shape defects.

BRIEF DESCRIPTION OF THE PRIOR ART In manufacturing of the metal strip, several processes, like rolling, annealing and tempering are used.-

As a metal strip is processed, the defects concerning the shape of the metal strip like guttering, curling, edge wave, full center and quarter buckle appear. These defects will not only be obstacles in following processes, but also a large factor in lowering the quality standard of the product for which the metal strip is used. Therefore, it is necessary for the metal strip to be leveled by using some kind of leveler. Generally, in the processing of the leveler, the metal strips having shape defects are bent plastically several times by the work rolls. The plastic deformation corrects the shape defects. In order to correct the shape defects, such as curling, the bending of the metal strip by a conventional roller leveler is sufficient. But recently a thinner metal strip is required by the users of metal strips. In producing thinner metal strips, it is more difficult to get a good shape for the metal strip than in producing metal strips of regular thickness. In order to correct shape defects other than curling of the thinner and harder metal strip, tension is added to the metal strip by using bridles before and after the leveler station besides'bending by the work rolls. This type of leveler is called a mechanical tension leveler. The present invention contemplates a new and economical method and apparatus against the conventional mechanical tension leveler.

In the conventional mechanical tension leveler, the mechanism of supporting the work rolls is complicated and a number of bearings have to be used to support the back up rolls. Moreover, in orderto equalize the circumferential speed of many work rolls to the speed of the traveling metal strip, a large scale and complicated speed control system needs to be installed. But it is not possible to obtain precise speed even when the speed control system is installed because the metal strip is elongated gradually passing the work rolls and therefore the circumferential speeds of the work rolls must be different to keep up with the speed of the traveling metal strip. When the metal strip is leveled by the conventional mechanical tension leveler, there is often such difficulties as stains on the surface of the metal strip due to leakage of oil-out of the bearings and the scratches on the surface of the metal strip due to the slip between the surfaces of the work roll and of the metal strip. Because of the complicated mechanism, it is very difficult to use work rolls of the extremely small diameter. Therefore, large tension is required to level the metal strip and the large scale bridles have to be installed before and after the conventional tension leveler. But when large tension is applied for a thin and hard metal strip, it will occassionally break and the operation of leveling becomes dangerous. Moreover, installation of the large scale bridles requires a large investment of capital, which is not economic.

In the US. Pat, Nos. 2,295,017 and 3,064,712, the supplementary bearings are used in the roller leveler.

But the object of those inventions are quite different from the present invention and also the way in which the work roll floats out of the bearing surface is different.

OBJECT OF THE INVENTION An object of the invention is to provide a method and apparatus in which extremely small work rolls can be used in the leveling system.

Another object of the invention is to provide a methodand apparatus in which a special speed control system of the rolls is not necessary to equalize the circumferential speed of the work rolls to the speed of the traveling metal strip.

A further object of the invention is to provide a compact apparatus in which the large scale bridles before and after the leveler are not always required to correct the shape defects of the metal strip.

A still further object of the invention is to provide an arrangement wherein surface defects of the metal strip, such as scratches, do not appear during leveling.

SUMMARY OF THE INVENTION Briefly speaking, the invention contemplates making a work roll of small diameter float out of a bearing surface by supplying pressurized liquid to a bearing clearance between the work roll and the bearing surface, andgive plastic deformation of bending to the traveling metal strip under tension by pushing the work roll against the metal strip, and moreover equalize the circumferential speed of the work roll to the speed of the traveling metal strip, and finally correct the shape defects of the metal strip.

The invention as well as other objects and advantages thereof, will become more apparent from the following detailed description when considered together with the accompanying drawing, in which:

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTION In FIGS. 1 and 2, there is shown a support 1 and a work roll 2. A hole is drilled through the support 1' of the workroll 2 and the openings at both ends of the hole are closed by plugs 8 and 0 rings 9 to keep a chamber 3 airtight. An entrance 4 of the pressurized liquid to the chamber 3 is opened trhough the support 1 of the work roll 2. On the bearing surface 27, a slender recess 7 is provided. A hole 5 with an orifice 28 connects between the recess 7 and the chamber 3. The surface of the work roll 2 and the bearing surface 27 forms the bearing clearance 6, which is exaggerated in these figures.

II of FIGS. 3 and 4 are the side view and the cross section when taken along the line ll II of another example respectively. Instead of the hole 5 with the orifice 28 and the thin recess 7 in FIGS. 1 and 2, a row of capillaries 26 and divided small recesses 25 are provided in this example. A side guide 10 in FIGS. 1 and 3 acts to prevent the work roll 2 from moving along the axial direction.

FIG. 5 shows an example of a leveling unit which consists of the supports 1, the work rolls 2 and other devices. One of the supports 1 of the work roll is fixed to the lower frame 12 by using bolts 14 and other two supports 1 of the work roll 2 are set to the upper frame 11 by using long screws 13 in the way the position of the supports 1 can be adjusted above and below. The supply conduit pipes 15 are connected to the supports 1 of the work roll 2 to supply pressurized liquid to the chambers 3. The metal strip 24 to be leveled is guided to pass between the work rolls 2 on the supports 1. If necessary, a pair of squeeze rolls 16 are provided at the exit after the metal strip 24 is leveled and the discharge conduit pipe 17 is connected to the lower frame 12 to drain liquid used, which is reusable. Besides this example shown in FIG. 5, other types of arrangements of the leveling units can be assembled. In the support 1, the recess 7 'or 25 can be omitted depending upon the case and the chamber 3 can be provided outside the support 1 of the work roll 2. I

In FIG. 6, an example of the lever is shown including the leveling unit 18 which can be constructed in various ways. The metal strip 24 leaving the prior work station 22 travels trhough the front bridle and enters the leveling unit 18. After the metal strip 24 is leveled, it travels through the back bridle 21 and goes to the subsequent treatment 23. The supply conduit pipe 15 and the discharge conduit pipe 17 connect between the leveling unit 18 and the pressure source 19 which is provided to supply the liquid to the leveling unit 18. The metal strip 24is dragged by the front bridle 20 and the back bridle 21.

The positions of the supports 1 of the work roll 2 are adjusted so asto force each work roll 2 to contact the metal strip 24 under tension. At the same time, pressurized liquid is supplied through the supply conduit pipe 15 from the pressure source 19 which is set to supply the liquid under proper pressure and flow rate. The pressurized liquid enters the chamber 3 of the support 1 of the work roll, passes through the hole 5 with an orifice 28 or the capillary 26, gets to the slender recess 7 or the divided recess and discharges through the bearing clearance 6 between the work roll 2 and the bearing surface 27, so the work roll 2 floats out of the bearing surface 27 by the pressure film in the bearing clearance 6. Thereafter the metal strip 24 travels under the tension added by the front bridle 20 and the back bridle 21 in FIGS. 6 and 7. The part of the metal strip 24 which contacts the work roll 22 is deformed by bending and at the same time is elongated. The plastic elongation of the metal strip 24 corrects its shape defects.

The scratch on the surface of the metal strip 24 can be prevented because the work roll 2 floats out of the bearing surface and therefore rolls on the metal surface without slipping. Moreover, an expensive system is not necessary to drive the work rolls 2. Small tension is good enough to get the plastic elongation necessary to correct the shape defects of the metal strip 24 because the work rolls 2 of very small diameter can be used in the present invention. This means that the capacity of the front bridle 20 and the back bridle 21 in FIG. 6 can be small and when only small tension is required, even the bridle of the prior art used in the processing system can be utilized and there is no need to use a new bridle for the leveling unit of the present invention. The components of the system in such a case is as shown in FIG. 7. Any kind of liquid can be used as pressurized liquid, like water, oil and so on, which is used presently in the production line.

The result of leveling of the metal strip by using the present invention is shown in Table I. As shown in Table I, using the leveler of the present invention makes it easy to correct the shape defects of the extremely thin, high yield stress metal strip which is very difficult to be corrected by the conventional present mechanical tension leveler.

TABLE I Example 1 Example 2 Diameter of work roll 5 mm 5 mm Number of work rolls 3 3 Front tension between (20) and (18) I650 kg 1600 kg Back tension between (18) and (21) 3000 kg 2200 kg Pressurized liquid water lube Supply pressure of liquid 25 kg/cm 35 kg/em Flow rate of pressurized liquid I50 l/min l/min Strip thickness 0.l7 mm 0.? mm Strip width I000 mm I000 mm Strip yield stress 63 kglmm 56 kg/mm Height of edge wave before leveled 6 mm 5 mm Height of edge wave after leveled 0 mm 0 mm Plastic elongation 0.8 0.7

It will be understood that various changes and modifications can be made in the structures described above which provide the characteristica of this invention without departing from the spirit thereof particularly as defined in the following claims.

What is claimed is:

1. In an apparatus for leveling a metal strip to correct shape defects therein, an elongated support along which said metal strip is adapted to be fed, said elongated support forming a bearing surface, an elongated small diameter roll positioned over said support and over which said metal strip is fed in contacting relation therewith, said bearing surface constituting the sole support for said roll, said roll being mounted on said bearing surface in floating engagement therewith, passage means formed in said support for receiving pressurized liquid in communication with said bearing surface, means to supply pressurized liquid to said passage means to floatingly raise said elongated roll out of contact with said bearing surface enabling free rotation thereover and to force said elongated roll into pressure contact with said metal strip to place said metal strip under tension and correct shape defects therein, vertically disposed guide means formed on said elongated support confining said elongated roll against axial movement and guiding said elongated roll in its floating movement over said bearing surface in response to said liquid pressure means in this movement towards said metal strip.

2. An apparatus as in claim 1 and further including a frame member, means for adjustably mounting said elongated support on said frame member.

3. An apparatus as in claim 1, wherein a plurality of of said plurality of said elongated supports and rolls. elongated supports and a plurality of elongated rolls are 5 Apparatus as in claim 4 d f th i l di provided along which metallic.strip is posed frame members and means for adjustably mount- 4. Apparatus as in claim 3, wherein at least one elongated support and one elongated roll of said plurality 5 mg said opposed facing elongated Supports and rolls on of elongated supports and rolls are in opposed facing respectwe frame membersrelation to another of said elongated support and roll l Patent no, 3,812,701 Dated May 28, 1974 lnventofls) Yasnnom Miyamatsu et 31 It is certified that error appears ifi the aboveidentified patent and thatsaid Letters Patentarehereby corrected as shown below:

On the title-page, please insert the following:

---Claimsriority to Ja anese patent application No.

46/1035 4 filed Decem er 20, 1971.

Signed and sealed this 17th day of December 1974.

(SEAL) Attest:

McCOY Mi GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents RM PO-IOSO (10-55) USCOMM-DC 60376-P69 

1. In an apparatus for leveling a metal strip to correct shape defects therein, an elongated support along which said metal strip is adapted to be fed, said elongated support forming a bearing surface, an elongated small diameter roll positioned over said support and over which said metal strip is fed in contacting relation therewith, said bearing surface constituting the sole support for said roll, said roll being mounted on said bearing surface in floating engagement therewith, passage means formed in said support for receiving pressurized liquid in communication with said bearing surface, means to supply pressurized liquid to said passage means to floatingly raise said elongated roll out of contact with said bearing surface enabling free rotation thereover and to force said elongated roll into pressure contact with said metal strip to place said metal strip under tension and correct shape defects therein, vertically disposed guide means formed on said elongated support confining said elongated roll against axial movement and guiding said elongated roll in its floating movement over said bearing surface in response to said liquid pressure means in this movement towards said metal strip.
 2. An apparatus as in claim 1 and further including a frame member, means for adjustably mounting said elongated support on said frame member.
 3. An apparatus as in claim 1, wherein a plurality of elongated supports and a plurality of elongated rolls are provided along which said metallic strip is fed.
 4. Apparatus as in claim 3, wherein at least one elongated support and one elongated roll of said plurality of elongated supports and rolls are in opposed facing relation to another of said elongated support and roll of said plurality of said elongated supports and rolls.
 5. Apparatus as in claim 4, and further including opposed frame members and means for adjustably mounting said opposed facing elongated supports and rolls on respective frame members. 